Request For Comments - RFC7990

Internet Architecture Board (IAB) H. Flanagan
Request for Comments: 7990 RFC Editor
Category: Informational December 2016
ISSN: 2070-1721
RFC Format Framework
Abstract
In order to improve the readability of RFCs while supporting their
archivability, the canonical format of the RFC Series will be
transitioning from plain-text ASCII to XML using the xml2rfc version
3 vocabulary; different publication formats will be rendered from
that base document. With these changes comes an increase in
complexity for authors, consumers, and the publisher of RFCs. This
document serves as the framework that provides the problem statement,
lays out a road map of the documents that capture the specific
requirements, and describes the transition plan.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Architecture Board (IAB)
and represents information that the IAB has deemed valuable to
provide for permanent record. It represents the consensus of the
Internet Architecture Board (IAB). Documents approved for
publication by the IAB are not a candidate for any level of Internet
Standard; see Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7990.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document.
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1. Introduction
"RFC Series Format Requirements and Future Development" [RFC6949]
discusses the need to improve the display of items such as author
names and artwork in RFCs as well as the need to improve the ability
of RFCs to be displayed properly on various devices. Based on the
discussions with communities of interest, such as the IETF, the RFC
Series Editor decided to explore a change to the format of the Series
[XML-ANNOUNCE]. This document serves as the framework that describes
the problems being solved and summarizes the documents created to-
date that capture the specific requirements for each aspect of the
change in format.
Key changes to the publication of RFCs are highlighted, and a
transition plan that will take the Series from a plain text, ASCII-
only format to the new formats is described on the rfc-interest
mailing list [RFC-INTEREST].
This document is concerned with the production of RFCs, focusing on
the published formats. It does not address any changes to the
processes each stream uses to develop and review their submissions
(specifically, how Internet-Drafts will be developed). While I-Ds
have a similar set of issues and concerns, directly addressing those
issues for I-Ds will be discussed within each document stream.
The details described in this document are expected to change based
on experience gained in implementing the new publication toolsets.
Revised documents will be published capturing those changes as the
toolsets are completed. Other implementers must not expect those
changes to remain backwards compatible with the details described in
this document.
2. Problem Statement
There are nearly three billion people connected to the Internet
[ISTATS] and individuals from at least 45 countries have regularly
attended IETF meetings over the last five years. The Internet is now
global, and while the world has changed from when the first RFCs were
published, the Series remains critical to defining protocols,
standards, best practices, and more for this global network that
continues to grow. In order to make RFCs easily viewable to the
largest number of people possible, across a wide array of devices,
and to respect the diversity of authors and reference materials while
still recognizing the archival aspects of the Series, it is time to
update the tightly prescribed format of the RFC Series.
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All changes to the format of the RFC Series must be made with
consideration to the requirements of a wide set of communities over
an extended length of time. Examples of the preferences and specific
needs are those of existing authors and implementers, lawyers that
argue Intellectual Property Rights (IPR), educators, managers, and
policymakers that need to know what to list in potential Request for
Proposals (RFPs) for their organizations. The immediate needs of
today's communities must be balanced with the needs for long-term
archival storage.
3. Terminology
This document uses terminology from RFC 6949, repeated below for
convenience.
ASCII: Coded Character Set - 7-bit American Standard Code for
Information Interchange, ANSI X3.4-1986 [ASCII]
Canonical format: the authorized, recognized, accepted, and
archived version of the document
Metadata: information associated with a document so as to provide,
for example, definitions of its structure, or of elements within
the document such as its topic or author
Publication format: display and distribution format as it may be
read or printed after the publication process has completed
Reflowable text: text that automatically wraps to the next line in
a document as the user moves the margins of the text, either by
resizing the window or changing the font size
Revisable format: the format that will provide the information for
conversion into a Publication format; it is used or created by the
RFC Editor
Submission format: the format submitted to the RFC Editor for
editorial revision and publication
4. Overview of the Decision-Making Process
Requirements, use cases, concerns, and suggestions were collected
from the communities of interest at every stage of the project to
update the RFC format. Input was received through the rfc-interest
mailing list, as well as in several face-to-face sessions at IETF
meetings. Regular conversations were held with the Chairs of the
IETF, IRTF, IAB, and IAOC as well as the Independent Stream Editor to
discuss high-level stream requirements. Updates regarding the status
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of the project were provided to the IETF community during the IETF
Technical Plenary as well as Format BoFs or IAB sessions at several
IETF meetings [IETF84] [IETF85] [IETF88] [IETF89] [IETF90].
The output from the first year of discussion on the topic of RFC
format was published as RFC 6949, which provided the first solid
documentation on the requirements for the Series. RFC 6949 is a
product of the IAB stream (following the process described in
"Process for Publication of IAB RFCs" [RFC4845]). This is also the
case with all of the RFCs that informed the format update work.
After the high-level requirements were published, the RFC Series
Editor (RSE) brought together an RFC Format Design Team to start
working out the necessary details to develop the code needed to
create new and changed formats. The Design Team discussed moving
away from the existing xml2rfc vocabulary, but with such a strong
existing support base within the community and no clear value with
other XML vocabularies or schemas, the decision was made to work with
the xml2rfc version 2 (xml2rfc v2) [RFC7749] model and use it as the
base for the new format environment. Part of this discussion
included a decision to stop using an XML document type definition
(DTD) in favor of a Regular Language for XML Next General (RELAX NG)
model using a defined vocabulary. While the biweekly calls for this
team were limited to Design Team members, review of the decisions as
documented in the documents produced by this team was done publicly
through requests for feedback on the rfc-interest mailing list.
Several of the documents produced by the Design Team, including those
on xml2rfc v2 [RFC7749] and v3 [RFC7991] and the SVG profile
[RFC7996], were sent through an early GenART review [GEN-ART] before
starting the process to be accepted by the IAB stream.
While the IETF community provided the majority of input on the
process, additional outreach opportunities were sought to gain input
from an even broader audience. Informal discussions were held with
participants at several International Association of Scientific,
Technical, and Medical Publisher events [STM], and presentations made
at technical conferences such as the TERENA Networking Conference
2014 [TNC2014] and NORDUnet 2014 [NDN2014].
In order to respond to concerns regarding responses to subpoenas and
to understand the legal requirements, advice was requested from the
IETF Trust legal team regarding what format or formats would be
considered reasonable when responding to a subpoena request for an
RFC.
Given that several other standards development organizations (SDOs)
do not offer plain-text documents, and in fact may offer more than
one format for their standards, informal input was sought from them
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regarding their experience with supporting one or more non-plain-text
formats for their standards.
Finally, the entire process was reviewed regularly with the RFC
Series Oversight Committee [RSOC] and regular updates provided to the
IAB and IESG. They have offered support and input throughout the
process.
Where consensus was not reached during the process, the RSE made any
necessary final decisions, as per the guidance in "RFC Editor Model
(Version 2)" [RFC6635].
5. Key Changes
At the highest level, the changes being made to the RFC format
involve breaking away from solely ASCII plain text and moving to a
canonical format that includes all the information required for
rendering a document into a wide variety of publication formats. The
RFC Editor will become responsible for more than just the plain-text
file and the PDF-from-text format created at time of publication; the
RFC Editor will be creating several different formats in order to
meet the diverse requirements of the community.
The final XML file produced by the RFC Editor will be considered the
canonical format for RFCs; it is the lowest common denominator that
holds all the information intended for an RFC. PDF/A-3 will be the
publication format offered in response to subpoenas for RFCs
published through this new process and will be developed with an eye
towards long-term archival storage. HTML will be the focus of
providing the most flexible set of features for an RFC, including
JavaScript to provide pointers to errata and other metadata. Plain
text will continue to be offered in order to support existing tool
chains, where practicable, and the individuals who prefer to read
RFCs in this format.
6. Canonical Format Documents
6.1. XML for RFCs
Key points regarding the XML format:
o The canonical format for RFCs is XML using the xml2rfc version 3
(xml2rfc v3) vocabulary. The XML file must contain all
information necessary to render a variety of formats; any question
about what was intended in the publication will be answered from
this format.
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o Authors may submit documents using the xml2rfc v2 vocabulary, but
the final publication will be converted to use the xml2rfc v3
vocabulary.
o SVG is supported and will be embedded in the final XML file.
o There will be automatically generated identifiers for sections,
paragraphs, figures, and tables in the final XML file.
o The XML file will not contain any xml2rfc v3 vocabulary elements
or attributes that have been marked deprecated.
o A DTD will no longer be used. The grammar will be defined using
RELAX NG [RNC].
o The final XML file will contain, verbatim, the appropriate
boilerplate as applicable at time of publication specified by RFC
7841 [RFC7841] or its successors.
o The final XML will be self-contained with all the information
known at publication time. For instance, all features that
reference externally defined input will be expanded. This
includes all uses of xinclude, src attributes (such as in
<artwork> or <sourcecode> elements), include-like processing
instructions, and externally defined entities.
o The final XML will not contain comments or processing
instructions.
o The final XML will not contain src attributes for <artwork> or
<sourcecode> elements.
[RFC7749] describes the xml2rfc v2 vocabulary. While in wide use at
the time of writing, this vocabulary had not been formally documented
prior to the publication of RFC 7749. In order to understand what
needed to change in the vocabulary to allow for a more simple
experience and additional features for authors, the current
vocabulary needed to be fully described. RFC 7749 will be obsoleted
by [RFC7991].
[RFC7991] describes the xml2rfc v3 vocabulary. The design goals were
to make the vocabulary more intuitive for authors and to expand the
features to support the changes being made in the publication
process. It obsoletes RFC 7749.
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7. Publication Format Documents
7.1. HTML
[RFC7992] describes the semantic HTML that will be produced by the
RFC Editor from the xml2rfc v3 files.
Key points regarding the HTML output:
o The HTML will be rendered from the XML file; it will not be
derived from the plain-text publication format.
o The body of the document will use a subset of HTML. The documents
will include Cascading Style Sheets (CSS) for default visual
presentation; it can be overwritten by a local CSS file.
o SVG is supported and will be included in the HTML file.
o Text will be reflowable.
o JavaScript will be supported on a limited basis. It will not be
permitted to overwrite or change any text present in the rendered
HTML. It may, on a limited basis, add text that provides post-
publication metadata or pointers, if warranted. All such text
will be clearly marked as additional.
7.2. PDF
[RFC7995] describes the tags and profiles that will be used to create
the new PDF format, including both the internal structure and the
visible layout of the file. A review of the different versions of
PDF is offered, with a recommendation of what PDF standard should
apply to RFCs.
Key points regarding the PDF output:
o The PDF file will be rendered from the XML file; it will not be
derived from the plain-text publication format.
o The PDF publication format will conform to the PDF/A-3 standard
and will embed the canonical XML source.
o The PDF will look more like the HTML publication format than the
plain-text publication format.
o The PDF will include a rich set of tags and metadata within the
document.
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o SVG is supported and will be included in the PDF file.
7.3. Plain Text
[RFC7994] describes the details of the plain-text format; in
particular, it focuses on what is changing from the existing plain-
text output.
Key points regarding the plain-text output:
o The plain-text document will no longer be the canonical version of
an RFC.
o The plain-text format will be UTF-8 encoded; non-ASCII characters
will be allowed.
o A Byte Order Mark (BOM) will be added at the start of each file.
o Widow and orphan control [TYPOGRAPHY] for the plain-text
publication format will not have priority for the developers
creating the rendering code.
o Authors may choose to have pointers to line art in other
publication formats in place of ASCII art in the .txt file.
o An unpaginated plain-text file will be created.
o Running headers and footers will not be used.
7.4. Potential Future Publication Formats
7.4.1. EPUB
This format is intended for use by ebook readers and will be
available for RFCs after the requirements have been defined. No
document on this topic is currently available.
8. Figures and Artwork
8.1. SVG
[RFC7996] describes the profile for SVG line art. SVG is an XML-
based vocabulary for creating line drawings; SVG information will be
embedded within the canonical XML at the time of publication.
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9. Content and Page Layout
9.1. Non-ASCII Characters
There are security and readability implications to moving outside the
ASCII range of characters. [RFC7997] focuses on exactly where and
how non-ASCII characters may be used in an RFC, with an eye towards
keeping the documents as secure and readable as possible, given the
information that needs to be expressed.
9.2. Style Guide
The RFC Style Guide [RFC7322] was revised to remove as much page
formatting information as possible, focusing instead on grammar,
structure, and content of RFCs. Some of the changes recommended,
however, informed the XML v3 vocabulary.
9.3. CSS Requirements
[RFC7993] describes how the CSS classes mentioned in "HyperText
Markup Language Request for Comments Format" should be used to create
an accessible and responsive design for the HTML format.
10. Transition Plan
10.1. Statement of Work and RFP for Tool Development
Existing tools for the creation of RFCs will need to be updated, and
new tools created, to implement the updated format. As the
requirements-gathering effort, described in the various documents
described earlier in this document, finishes the bulk of the work,
the Tools Development Team of the IETF will work with the RSE to
develop Statements of Work (SoWs). Those SoWs will first be reviewed
within the Tools Development Team and the Tools Management Committee,
and it will then go out for a public comment period. After public
review, the SoWs will be attached to an RFP and posted as per the
IETF Administrative Support Activity (IASA) bid process [IASA-RFP].
Once bids have been received, reviewed, and awarded, coding will
begin.
10.2. Testing and Transition
During the I-D review and approval process, authors and stream-
approving bodies will select drafts to run through the proposed new
publication process. The RFC Editor will process these documents
after they have been approved for publication using xml2rfc v2 and
will simultaneously test the selected I-Ds with the xml2rfc v3
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process and tools. While the final RFCs published during this time
will continue as plain text and immutable once published, the
feedback process is necessary to bootstrap initial testing. These
early tests will target finding issues with the proposed xml2rfc v3
vocabulary that result in poorly formed publication formats as well
as issues that prevent proper review of submitted documents.
Feedback will result in regular iteration of the basic code and XML
vocabulary. In order to limit the amount of time the RFC Production
Center (RPC) spends on testing and quality assurance (QA), their
priority will be to edit and publish documents; therefore, community
assistance will be necessary to help move this stage along. A
mailing list and experimental source directory on the RFC Editor
website will be created for community members willing to assist in
the detailed review of the XML and publication formats. Editorial
checks of the publication formats by the community are out of scope;
the focus will be the QA of each available output, checking for
inconsistencies across formats.
The purpose of the testing phase is to work with the community to
identify and fix bugs in the process and the code before producing
canonical, immutable XML, and to collect additional feedback on the
usability of the new publication formats.
Any modifications to the document review process, up to and including
AUTH48, will happen with the community and the stream-approving
bodies as we learn more about the features and outputs of the new
publication tools. Defining those processes is out of scope for this
document.
Success will be measured by the closure of all bugs identified by the
RPC and the Tools Development Team as fatal in addition to reaching
rough consensus with the community on the readiness of the XML
vocabulary and final output files for publication. The actual
rendering engine can go through further review and iteration, as the
publication formats may be republished as needed.
Authors are not required to submit their approved drafts to the RFC
Editor in an XML format, though they are strongly encouraged to do
so; plain text will also remain an option for the foreseeable future.
However, documents submitted as plain text cannot include such
features as SVG artwork. The RPC will generate an XML file if
necessary for basic processing and subsequent rendering into the
approved output formats.
A known risk at this point of the transition is the difficulty in
quantifying the resources required from the RPC. This phase will
require more work on the part of the RPC to support both old and new
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publication processes for at least six months. There is potential
for confusion as consumers of RFCs find some documents published at
this time with a full set of outputs, while older documents only have
plain text. There may be a delay in publication as new bugs are
found that must be fixed before the files can be converted into the
canonical format and associated publication formats.
10.3. Completion
Authors may submit XML (preferred) or plain-text files. The XML
files submitted for publication will be converted to canonical XML
format and published with all available publication formats. All
authors will be expected to review the final documents as consistent
with the evolving procedures for reviewing documents.
Success for this phase will be measured by a solid understanding by
the RSE and the IAOC of the necessary costs and resources required
for long-term support of the new format model.
11. Security Considerations
Changing the format for RFCs involves modifying a great number of
components to publication. Understanding those changes and the
implications for the entire tool chain is critical so as to avoid
unintended bugs that would allow unintended changes to text.
Unintended changes to text could in turn corrupt a standard,
practice, or critical piece of information about a protocol.
12. References
12.1. Normative References
[RFC6949] Flanagan, H. and N. Brownlee, "RFC Series Format
Requirements and Future Development", RFC 6949,
DOI 10.17487/RFC6949, May 2013,
<http://www.rfc-editor.org/info/rfc6949>.
[RFC7749] Reschke, J., "The "xml2rfc" Version 2 Vocabulary",
RFC 7749, DOI 10.17487/RFC7749, February 2016,
<http://www.rfc-editor.org/info/rfc7749>.
[RFC7991] Hoffman, P., "The "xml2rfc" Version 3 Vocabulary",
RFC 7991, DOI 10.17487/RFC7991, December 2016,
<http://www.rfc-editor.org/info/rfc7991>.
[RFC7992] Hildebrand, J., Ed. and P. Hoffman, "HTML Format for
RFCs", RFC 7992, DOI 10.17487/RFC7992, December 2016,
<http://www.rfc-editor.org/info/rfc792>.
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